Abstract: A locking and control device consisting of a hexalobular, or star security headed machine screw, which screw can be modified for security reasons by closing off the star interstices and removing its corresponding screwdriver lobes such that when the machine screw head is inserted into a hole drilled through a door or door frame, being part of a doorway, and secured there by means of a base mounting plate screwed to the inside of the door, or door frame, the machine screw head can be accessed through the said hole by means of a corresponding screwdriver such that when the machine screw head is turned by the screw-driver so also will the lock bolt, or some other means to be controlled such as a slide plate or electrical switch attached to the machine screw end be turned thus locking or unlocking the door or operating the other said devices.

Abstract: As herein described a plastic or metal hollow frame device which when mounted within the bolt cavity on a door frame and therefrom extending outwards with curved ‘U’ shaped arms through the strike plate aperture mounted concentric with and above the said frame bolt cavity, and thence into the space between the door frame and the edge of the closed door, i.e. the door gap, upon which door is mounted an associated spring bolt door lock, in such a manner that when the spring bolt is located within the strike plate aperture and the frame bolt cavity, i.e.

Abstract: A Spring Bolt Guard consisting of a metal or plastic ‘U’ shape with a base plate, wherein a locating screw hole has been drilled, which base plate extends out into the ‘U’ shape from the base of the ‘U’ shape such that when the described form is screwed into the spring bolt retaining cavity cut into the door frame the top of the ‘U’ shape fills the gap between the door frame and the door edge thus preventing plastic or metal shims being used to force the spring bolt back into the lock housing and by this means allowing the door to be illegaly opened without the use of a key.

Abstract: A device for attaching to a door knob which comprises a metal strip which has an arced width which clamps on to two peripheries of the door knob and which arced surface is also curved to encircle and contact 90% of the door knob diameter and which curved section has two free ends which are pulled into a tubular section by means of a hook bolt and end nut, the whole being assembled on to the door knob without the use of any tools or other attaching means and which complete device can be readily attached and removed for further installation on other door knobs as required.